DE 24 49 443 A1 describes a screw-in nonreturn valve, the valve housing of which takes up a comparatively large space in the radial direction. This is due to the fact that the diameter of the valve housing is composed in the least favourable case, owing to the arrangement of the individual functional units, of the cross-sections of the external thread, the valve housing portion of the valve housing, the valve body and the flow duct between the valve housing portion and the valve body, which are each suitably dimensioned in accordance with their function.
In the axial direction, too, the nonreturn valve of DE 24 49 443 A1 has a comparatively large extent. The comparatively large axial extent results from the addition of the geometry of the axially arranged functional units of the valve seat body, the valve body and the tension spring, as well as an additional space for a screwing tool which engages in each case on the inner surfaces of the valve housing for the screwing of the nonreturn valve.